Interleukin-1 (IL-1) plays a key role in the pathology of osteoarthritis or intervertebral disc degeneration/prolapse. The biological antagonist, interleukin-1 receptor antagonist (IL-1Ra), intervenes in the physiological mechanism of these diseases. IL-1Ra is a naturally occurring, structural derivative of IL-1 that competitively binds to the receptor and inhibits the biological effects of IL-1. The endogenous effects of IL-1ra are anti-inflammatory in nature, opposite to that of IL-1. A minimum IL-1ra/IL-1β ratio of 10:1 is required to inhibit IL-1 activity.
It has been known for some years that IL-1Ra can be synthesized by recombinant methods. However, autologous IL-1Ra, like all autologous proteins that are intrinsic to the body, is advantageous because the natural post-translational modifications such as glycosylations are already present. This is not the case with recombinant proteins because they are produced in prokaryotic hosts.
Stimulation of monocytes by adherent immunoglobulin G to form the interleukin-1 receptor antagonist is described by Arend and Leung in Immunological Reviews (1994) 139, 71-78 and Moore et al. in Am. J. Respir. Cell Mol. Biol. (1992) 6, 569-575. Andersen et al. in Autoimmunity (1995) 22, 127-133 explains that the therapeutic effect of immunoglobulin G to be observed in vivo cannot be attributed to an enhanced formation of interleukin-1 receptor antagonist, and that the in vitro formation of the interleukin-1 receptor antagonist (IL-1Ra) by monocytes depends on serum and plasma constituents adsorbed on polypropylene. The therapeutic use of adsorbed serum and plasma constituents to stimulate the formation of therapeutically interesting proteins in therapies is not only very costly but also involves the risk of contamination with infectious particles with which the serum and plasma constituents may be contaminated.
U.S. Pat. Nos. 6,713,246 and 6,759,188 to Reinecke disclose a method for producing IL-1Ra which can be employed directly in the therapy without using adsorbed serum and plasma constituents. Specifically, Reinecke provides a method for producing IL-1Ra in a special syringe made of glass, quartz or a plastic, the syringe being filled with blood, and incubated, to form the IL-1Ra being formed. The internal structure of the Reinecke syringe consists of a special material, in particular a glass, plastic, quartz and/or corundum, the surface of which is modified with the aid of a corrosive agent (chromosulphonic acid). The syringe is filled with a patient's blood and incubated to form IL-1Ra. The blood enriched with the protein is then centrifuged (to remove solid constituents such as blood platelets) and the serum containing IL-1Ra is reinjected into the patient (for example, into a diseased joint of the patient).
The syringe used by Reinecke has its inner surface textured by the acid and further includes glass beads to increase the internal surface area of the syringe and, thus, to provide a larger inducing surface. The glass beads, with a diameter of from 1 to 5 mm, occupy no more than 50% of the internal volume of the syringe. In Reinecke's method, the syringe is used to remove the patient's blood, to process the blood (to produce IL-1Ra), and then reinject the autologous IL-1Ra back into the patient. The present invention expands upon this method, to produce autologous IL-1Ra in a more efficient manner.